This resource is designed as a supporting resource for the HHMI 2013 Holiday Lecture on Science entitled, Medicine in the Genomic Era. The interactive animation illustrates how two different cell lineages are formed during development and that mutations can occur in either. Supporting resources included the various lectures and stories included in the Medicine in the Genomic Era series as well as a static poster of the interactive animation (http://www.hhmi.org/biointeractive/genetic-mutations-and-disease),